The invention relates to an arrangement for the stationary determination of leaks in a tank venting system installed in a vehicle with an internal combustion engine by which the venting system can be checked when the vehicle is not operated.
DE-OS 42 03 100 discloses an arrangement for the testing of the operation of a tank venting system of a vehicle with internal combustion engine. Herein functional testing is performed on board, that is, during vehicle operation. For that purpose the regeneration valve is opened for a predetermined period under predetermined operating conditions such that the vacuum existing in the engine induction manifold is applied to the tank venting system. Subsequently the vacuum achieved in the tank venting system is measured and the vacuum build-up gradient is determined. Then the regeneration valve is closed and, again after a given period, the remaining residual pressure is measured from which the pressure restitution gradient is determined. The quotient of the vacuum build-up and the pressure restitution gradients are then compared with a threshold value and a functional fault condition is indicated it the quotient exceeds the threshold value.
DE 41 24 465 A1 discloses a similar arrangement wherein pressurized air needed for leak testing is provided by a pressurized air source carried in the vehicle. However such on-board diagnosis arrangements are involved and expensive. In addition it is not possible with these arrangements to determine the size and location of a leak. It is the principal object of the present invention to provide an apparatus for the stationary determination of the soundness of a vehicle tank venting system with which leaks can be easily and reliably detected and also be located.